Hazardous Air Pollutants

There are currently 185 HAPs, or air toxics, regulated under the Clean Air Act. The original list of 188 air toxics can be found at http://www.epa.gov/ttn/atw/188polls.html . These pollutants have been associated with a wide variety of adverse human health effects such as cancer and reproductive or birth defects and adverse ecological effects. They are emitted from a variety of sources, including major sources such as power generators, incinerators and pulp and paper mills, area sources such as auto body shops, dry cleaners and other small businesses, and mobile sources such as cars, trucks, aircraft and other vehicles. Examples of toxic air pollutants include benzene, which is found in gasoline; perchloroethylene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper. Other examples of air toxics include dioxin, asbestos, toluene and metals such as cadmium and mercury

Exposure to toxic air pollutants at sufficient concentrations and duration may result in an increased chance of getting cancer or experiencing other serious health effects. These health effects can include damage to the immune system, as well as neurological, developmental, respiratory and other health problems. In addition, some toxic pollutants make their way into the food chain and can be magnified many times as they move their way up through the chain. Animals can also experience health problems if exposed to sufficient quantities of air toxics over time. Exposures can occur by breathing contaminated air, eating contaminated food, drinking contaminated water, ingesting contaminated soil and through skin contact.

Very few of the 185 HAPs identified by EPA have actual standards developed for them. Some such as hexavalent chromium, perchloroethylene and toluene have either State of Maine 24 hour or annual standards. Most of the others have guidelines set by the Department of Human Services for exposure.

Ambient air monitoring (24 hour samples) for hazardous air pollutants has been conducted at various locations throughout the state for varying lengths of time. Starting several years ago the Bureau began a long term trend monitoring program at five sites around the state. The five sites are located in Rumford, Portland , Lewiston , Bangor and Presque Isle. The program initially was looking for around 58 different compounds using the EPA Method TO-15. Since a lot of these compounds were never detected the laboratory began using a selective ion mode method for the analysis. This method looks for fewer compounds and is able to detect them at lower concentrations. The list of compounds that are currently being analyzed for and some of the data that has been collected is available in the latest annual air quality report .